1. Field of the Invention
The invention relates to a method and apparatus for processing a video signal, for example, for reducing an amount of noise in the video signal. The invention also relates to a television signal receiver comprising such an apparatus.
2. Description of the Related Art
European Patent Application EP-A-0,581,059 discloses a method of recursive noise reduction in television or video signals by means of a circuit arrangement comprising a noise reduction circuit, whose first input signal is the television or video signal, and whose second input signal is the low-frequency part of the output signal of the noise reduction circuit delayed over a field period by means of a field delay circuit. A decimating filter is arranged between the output of the noise reduction circuit and the input of the field delay circuit for reducing the data rate, which allows that a field delay circuit with a smaller storage capacity is used. The decimating filter comprises a low-pass filter for reducing the bandwidth by a factor 2, a quantizer for reducing the amplitude resolution from 8 bits to 7 bits, and a circuit for reducing the data rate by a factor 2. An interpolating filter is arranged between the output of the field delay circuit and the second input of the noise reduction circuit for increasing the data rate.
Experimentally it was found that still artifacts can be introduced in clean pictures.